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Carbon fiber-reinforced polymer Please check Affiliations if captured/presented correctly.(CFRP) composites are essential in aerospace, automotive, and civil engineering due to their strength-to-weight ratio, stiffness, thermal stability, and corrosion resistance. However, drilling CFRPs is challenging due to anisotropy, heterogeneity, and sensitivity to cutting forces, often causing delamination, burr formation, tearing surface ca[vities, and roughness. This review examines advancements in drilling techniques, analyzing their mechanisms, benefits, and limitations to improve hole quality and minimize damage. Finite element modeling (FEM) plays a crucial role in optimizing drilling by predicting thrust forces, torques, and damage, with recent advancements enhancing damage reduction. The review explores the influence of drilling parameters on thrust force, torque, temperature, and various damage types in CFRP composites. This review proposes strategies to optimize these parameters, including tool geometries, deburring techniques, pilot holes, and variable feed rates, while emphasizing sustainability for environmental and efficiency benefits. It analyzes research shortcomings, outlines future directions, and focuses on sustainable methods like cryogenic cooling, MQL, and compressed air cooling to reduce energy use, tool wear, and emissions. Future research should reveal the mapping mechanism between these parameters and CFRP hole-making quality, proposing an optimized, sustainable drilling strategy to reduce defects and improve hole quality. [ABSTRACT FROM AUTHOR]

This paper presents the influence of the preparation of the inspected surface on the deviations obtained when measuring the basic roughness parameters using the contact method. The problems described in the article are often encountered in industry when measurements are performed in mass production conditions, where a short measurement time is extremely important. Presented are the measurement results of five samples made of 1.0503 steel after the grinding process, subjected to various methods of preparation for roughness measurement: sample immediately after treatment, sample after treatment and after evaporation of liquid part of the coolant, sample after blowing with compressed air, sample after blowing with compressed air and washing in isopropyl alcohol, and the sample after blowing with compressed air and washing with acetone. The measurement results obtained from the contact profilometer provide the basis for developing recommendations regarding the preparation of surfaces for inter-operational and final measurements in the production process. [ABSTRACT FROM AUTHOR]

This work presents a versatile and cost-effective spray setup that integrates both compressed air spray and electrospray techniques, specifically designed for small-scale laboratory use. This setup provides researchers with an accessible tool to explore spray methods for growing battery electrodes. While these techniques hold significant industrial promise, affordable and simple methods for their use in research settings have been limited. To address this, the setup includes custom control software and detailed information on costs and materials, offering an easy-to-implement solution. The system was tested with three samples per technique, using identical settings, to evaluate the repeatability of each method and gain insights into the uniformity and structure of the resulting films. The structural and morphological characteristics of the samples were analyzed using X-ray diffraction and scanning electron microscopy. The air-spray samples showed greater consistency and repeatability, whereas the electrospray samples exhibited better deposition results in terms of material coverage and higher crystallinity films. Cracking was observed in the air-spray samples, which was related to thermal stress, and both techniques exhibited solvent evaporation issues. The issues encountered with the setup and samples are summarized, along with possible solutions and the next steps for future upgrades and research. [ABSTRACT FROM AUTHOR]

Improving the mixing homogeneity of heterogeneous powder in real time plays an essential role in ensuring the forming quality of functionally graded materials (FGM) produced by laser-directed energy deposition (L-DED). In order to achieve a high performance of material composition and proportion control as forming FGM parts, this paper investigates the mixing mechanism of several typical powders including 316L and NiCrCoAlY used for the L-DED process driven by compressed gas. An innovative pneumatic powder mixer is designed and optimized by the CFD-DEM simulation method to analyze the mixing characteristics of heterogeneous particles. To improve the real-time mixing homogeneity of different mixing ratios in the conveying process, mixing experiments based on differences in powder properties were conducted by the additive-subtractive composite machining center, and a coefficient of variation method was proposed to describe the mixing homogeneity of non-uniform powders. The results of micro-morphology and EDS indicate that the mixing quality of the two-phase flow is significantly enhanced with the four 45° compression inlets and 2 m/s inlet velocity structure. The results show that the numerical analysis method proposed in this paper can effectively describe the mixing law of heterogeneous particles, and the compressed air intake velocity should not exceed the initial two-phase flow velocity. The horizontal and vertical components generated by the compressed air intake at 45° are more conducive to the formation of favorable perturbations to the two-phase flow, and the number of four and eight compressed air intakes that act uniformly on the flow field is more appropriate. After a certain period of time, the two-phase flow with low error of mixed powder quality can be produced continuously. The mixed powder quality is obviously improved after the disturbance of compressed air intake. The mixing uniformity of powder with low spherical particle proportion can be effectively improved by increasing the preset mixing proportion of non-spherical particles. [ABSTRACT FROM AUTHOR]

In this study, a solar-driven combined cooling-heating and power system is proposed to achieve higher energy efficiency. Influences of compression ratio and direct normal irradiance are reported to evaluate the impact of design parameters. A compressed air energy system technology is utilized in the solar-driven Brayton cycle to run it in the peak consumption time, and a Rankine cycle is employed as an axillary cycle for more power generation. Results prove that the proposed system provides 11.75 MW pure power besides 3.2 MW heating and 6.8 MW cooling loads and it is able to run 5 hr in compressor deactivated mode passing peak consumption hours. Overall energy efficiency of the proposed system is estimated by more than 55% considering solar inlet beams energy, and 89% ignoring solar tower energy loss. The most exergy destructor component of the proposed system is solar heat absorber by 72% of general system destructed exergy. [ABSTRACT FROM AUTHOR]

The saturated impulse is a special phenomenon in the dynamic plastic behavior of engineering structures under intensive pulse loading, such as slamming loading. In this study, slamming experiments were performed on steel plates to investigate their slamming pressure and dynamic plastic responses, as well as the saturation phenomenon, and elucidate the effect of the plate thickness and material properties on the dimensionless saturated deflection and saturated impulse in combination with the published test data. The results show that the dimensionless saturated deflection and saturated impulse of the test plates gradually increased as the dimensionless stiffness decreased. After being validated against the experimental results, a numerical method that considered the fluid–structure interaction (FSI) effect was then employed to provide comprehensive insight into the transient plastic responses and saturated impulse of the flat plates under slamming impact. Numerical simulations revealed that the compressed air layer always existed during the effective process of the flat slamming impact. Through the numerical prediction of the dynamic plastic deflection and slamming pulse loading, it was observed that the saturated impulse phenomenon always took place after the time instant of the peak value of the pressure pulse. Furthermore, the analysis of the saturated impulse based on the numerical simulations indicated that the saturation phenomenon was more likely to be achieved as the water impact velocity increased. [ABSTRACT FROM AUTHOR]

The purpose of this paper was to study in vitro atomization properties of the self-developed sodium sivelestat for inhalation, evaluate the feasibility of this preparation as an aerosol inhalation, and provide the guidance for the following animal administration experiment. Firstly, in order to ensure accurate, uniform and stable doses of the self-developed product after administration, its atomization performance was analyzed through the testing of fine particle mass and the total emitted dose, and the results of its atomization parameters meet the requirement of inhalation. Next, Atomization characteristics of two commonly used nebulizers, air compressed nebulizer and mesh nebulizer, were studied and compared. The results showed that mesh atomizers have a smaller and more uniform particle size distribution. And then, the experiment of acute lung injury induced by aerosol inhalation of lipopolysaccharide in mice was used to test the therapeutic effect of our self-developed formulation, and compared with the positive control (sodium sivelestat for injection). The results showed that inhalation had a lower concentration and was equally effective than injection of sodium sivelestat. All the results support that the self-developed sodium sivelestat can be used as an aerosol inhaled drug. [ABSTRACT FROM AUTHOR]

Effective planning of the cavern field involves determining the optimal pillar width between the caverns and the feasible number of caverns based on geological and mining conditions. The proper design of the pillar width is crucial to ensure the stability of the cavern field and the rational utilization of the rock salt deposit. The stability of the pillars is a complex problem influenced by various factors, including rock salt creep, changes in the cavern pressure during operational cycles, mechanical parameters, and failure criteria of the rock salt. To address this problem, the stability of the cavern field in relation to the number of caverns and pillar widths is evaluated. The evaluation is based on the following criteria: displacements, von Mises stress, strength/stress ratio, and safety factor. Three variations of pillar width and three variants of cavern fields, differing in the number of caverns, are considered. Results show that the allowable pillar width is affected by the number of caverns in the cavern field. Moreover, the stability analysis reveals uneven stress and deformation distribution in the cavern field. When the pillar width is 2.0–3.0 times the diameter of a cavern, pillars at the centre exhibit poorer stability than those at the edges of the cavern field. However, with a narrower pillar width, the highest displacements occur at the field's edges. The findings of this study provide a valuable date in the planning, design, and operation of new cavern fields for the underground storage of energy sources such as oil, natural gas, hydrogen, and compressed air in rock salt deposits. [ABSTRACT FROM AUTHOR]

In 2007, the Littoral Acoustic Demonstration Center conducted a comprehensive experiment in the northern Gulf of Mexico to measure the three-dimensional acoustic field of a standard marine compressed-air source array used in seismic exploration. This study aims to enhance understanding of long-range acoustic propagation of the array signals, with focus on variations in received sound pressure levels and sound exposure levels (SELs) at various ranges from the source. These variations are influenced by factors, such as receiver depth, array orientation, and propagation conditions. The long-range measurements show that received peak pressure levels and SELs exhibit non-monotonic (oscillatory) behavior with range leading up to 10 dB increase in received levels at longer ranges. At ranges beyond 20 km, acoustic levels at the shallowest hydrophone consistently surpassed those at deeper ones by 3–10 dB, suggesting the impact of surface duct propagation effects. The results demonstrate that range-independent bathymetry leads to approximately 4 dB higher received acoustic levels than range-dependent propagation conditions. The measured long-range propagation acoustic metrics from controlled experiment provide a unique and critical dataset for validating both source and propagation model accuracy in predicting received sound pressure and SEL in the far-field of the source array. [ABSTRACT FROM AUTHOR]

Highlights: Extraction of sample from core using computer numerical control milling in fragile and water sensitive rock formations at any orientation. Milling is performed using an end-mill and sub-freezing compressed air thus eliminating surface erosion and fluid invasion. The proposed milling protocol shows about 85% success rate in extraction of testable samples in any direction to the bedding plane. [ABSTRACT FROM AUTHOR]

• Effect of L/D ratios and swirl generator materials was analyzed and discussed. • Thermal separation was enhanced by low thermal diffusivity vortex generator. • Optimum L/D ratio and operating conditions were indicated by isentropic efficiency. • Non-metal swirl generator integrated with a metal vortex tube was recommended. The current research investigates the effects of the swirl generator material, the tube length to diameter (L/D) ratio, and the vortex tube housing material on its performance. Two vortex tube were designed and constructed using either stainless or brass. In addition to testing different materials for the housing, 5 different materials were examined as potential options for the swirl generator, including stainless steel, brass, polyamide, acrylic and wood. All were having nozzle number of 6. The study encompassed three main areas: examining the impact of various L/D ratios on an entirely stainless vortex tube (ESVT) and an entirely brass vortex tube (EBVT), exploring various swirl generator materials at an optimal L/D ratio for the stainless vortex tube and the brass vortex tube, and investigating the influence of an optimal swirl generator material with varying L/D ratios for the stainless and brass vortex tubes. Operating conditions were controlled for all tests, the natural refrigerant, compressed air was used, the inlet pressure was set to 3.0 bar and the cold mass fraction was varied from 0.40 to 0.90. The results revealed that the performance of the ESVT was greater than the EBVT. The best combination was the polyamide swirl generator and brass vortex tube with an L/D ratio of 19.0. This resulted in the maximum isentropic efficiency of 0.27 at a cold mass fraction of about 0.47. [ABSTRACT FROM AUTHOR]

This paper will develop the restoring model of a commercial pneumatic artificial muscle (PAM) based on a McKibben structure, which comprises an elastic element connected with a viscoelastic element in parallel. The elastic element is generated by compressed air inside the rubber bellow; meanwhile, the viscoelasticity is affected by the rubber material. In particular, the viscoelastic property of the rubber material is proposed based on the Maxwell model. Instead of derivative of integer orders, an equation of motion of the fractional model is introduced to better capture the amplitude- and frequency-dependent property of the viscoelasticity of the PAM. The equation expressing the hysteresis loop due to the viscoelasticity of the PAM material will then be analyzed and built. A water cycle algorithm is employed to determine the optimal set of the proposed model. To evaluate the effectiveness of the proposed model, a comparison between the simulation calculated from the proposed model and experimental data is considered under harmonic force excitation. This study's results give potential insight into the field of system dynamic analysis with the elastic element being PAM. [ABSTRACT FROM AUTHOR]

Copyright of Smart Rail Transit is the property of Smart Rail Transit Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The current work presents an approach for the optimization of machining parameters on the turning of Al7075-T6 aerospace alloy. The alloy was turned on a lathe machine equipped with four different metalworking fluid (MF) setups: minimum quantity lubrication (MQL), Ranque–Hilsch vortex tube (RHVT), compressed air, and dry cutting using coated carbide tools. Taguchi technique was considered for the design of the L16 experimental array with three variable factors and four levels, and S/N ratios were obtained. The turning parameters feed rate and cutting speed are optimized in the experiment, taking into account responses such as surface roughness and tool wear. ANOVA determined the significant parameters that majorly influenced the responses. The results demonstrated that the condition of machining (<99% probability) was the most influential parameter followed by cutting speed (<95% probability) which affects the surface roughness and tool wear. Moreover, turning with MQL at a low cutting speed represented the optimum machining setup for reducing surface roughness and tool wear of this alloy. It was due to the fact that MQL decreases the friction between the tool and the workpiece which reduce the mechanical and thermal stresses on the cutting tool, resulting in lessened tool flank wear and effectively improving the surface quality. [ABSTRACT FROM AUTHOR]

In recent years, the research in the field of medicinal plants as therapeutic supplements has increased significantly. Lavender extract is widely used among medicinal plant products due to its unique therapeutic properties. Since drying processes require high energy, this study was conducted to study the performance of the spray dryer in the production of lavender extract powder at three levels of air temperature 150°C, 180°C, and 210°C, three levels of compressed air flow rate 6, 8, and 10 L/min and ratios of maltodextrin‐drying aid to the mass of dry matter of the extract 0%, 25%, and 50% by response surface method. For this purpose, the energy efficiency and exergy of the powder production process were examined. According to the obtained results, increasing the inlet air temperature and the inlet air flow rate increased the energy efficiency and exergy and decreased the energy efficiency and exergy, respectively. The energy efficiency of the drying process varied in the range of 6.55%–15.87%, and the exergy efficiency (ηex) of the drying process in the range of 2.87%–5.84%. Also, the ηex of the spray dryer was calculated in the range of 20.05%–38.78%. Based on the energy efficiency and exergy, the optimal production of lavender plant extract powder was obtained at the air temperature of 210°C, the compressed air flow rate of 6 L/min, and the amount of drying aid of 11.9 g/L. [ABSTRACT FROM AUTHOR]

In this work, three cooling strategies were proposed to increase the cooling rate and avoid extensive exposure to higher temperatures during the manufacturing of components in Inconel 625 using wire arc additive manufacturing (WAAM): forced cooling with compressed dry air jet, interpass idle time and the combination of both strategies. These strategies were compared for two welding technologies within gas metal arc welding (GMAW) process: pulsed and cold metal transfer (CMT). The results show that deposition using the GMAW-CMT welding mode showed better quality and uniformity than the GMAW-pulsed mode. The tested interpass idle time did not cause a significant effect on the mechanical properties, while the forced cooling using an air jet slightly improved the properties and may be used to increase productivity, especially for larger components. [ABSTRACT FROM AUTHOR]

Pulse-jet cartridge filters are widely used in industrial dust removal. However, the accumulation of highly sticky dust can cause irreversible blockage of cartridges. This is primarily due to the humidity of the air on the cleaning performance of the filter cartridge. Therefore, this article proposed a new method to solve it by changing the injection air source (nitrogen, compressed air after suction dryer treatment and compressed air after cold dryer treatment), the influence of humidity on system strength and dust residues was assessed. We define absolute humidity above 10 g m−3 as a high humidity condition and vice versa as a low humidity condition. The conclusions are that the injection effect only considers the water content of the injection air source: nitrogen > compressed air after suction dryer treatment > compressed air after cold dryer treatment. In low humidity conditions, the injection air source is the main influence factor, plus the water content of the injection air source, the greater the resistance of the system and the dust residues. In high humidity conditions, the humidity of the air is the most important influence. When the gas-solid concentration and filtration wind speed are constant, the system strength and dust residues increase with the increase in humidity. This study provides new ideas and reliable data sources for the industrial collection of adhesive dust. [ABSTRACT FROM AUTHOR]

Copyright of Rudarsko-Geolosko-Naftni Zbornik is the property of Faculty of Mining, Geology & Petroleum Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A non-contact piezoelectric actuator is proposed. The non-contact power transfer between stator and rotor is realized by pneumatic transmission, characterized by fast response, long life, compact structure, and easy miniaturization and control. The structure of the non-contact piezoelectric actuator is designed and its working principle is elucidated. The equation of the relationship between the output displacements of the non-contact piezoelectric actuator's micro-displacement amplifying mechanism and the input displacements of piezoelectric stack is deduced, and the simulation analysis method of output displacement of the micro-displacement amplifying mechanism is established. Using the equation and the simulation analysis, the output characteristics of micro-displacement amplifying mechanism for the non-contact piezoelectric actuator and their changes along with the system parameters are investigated. The detailed process of optimal design of the micro-displacement amplifying mechanism is given by means of mathematical statistics. The prototype is made and the performance test is carried out. The correctness of the theoretical calculation and simulation analysis is verified by comparing the experimental values with the theoretical and simulated values of the output displacement of the micro-displacement amplifying mechanism. The results show that the initial angle of bridge structure I has an obvious effect on the output characteristics of the micro-displacement amplifying mechanism in the range of 5°–15°. When the lever's rod length is 13 mm–15 mm, the bridge structure II's rod length is 6 mm–7 mm, and the power arm length of bridge structure I's driving lever is 5 mm–7 mm, the bridge structure II's rod horizontal projection length is 5 mm–6 mm and the output displacement of the micro-displacement amplifying mechanism is larger. Through the optimal design, it is obtained that the bridge structure I's initial angle is 8°, the lever's rod length is 15 mm, the bridge structure II's rod length is 7 mm, and the power arm length of bridge structure I driving lever is 5 mm, the bridge structure II's rod horizontal projection length is 6 mm, and the simulated output displacement of the micro-displacement amplifying mechanism is 0.1415 mm. The prototype test reveals that as the input excitation displacement decreases, the error increases, while as the input excitation displacement increases, the error decreases. Specifically, when the input excitation displacement is 0.005 mm, the measured output displacement of the micro-displacement amplifying mechanism is 0.1239 mm, resulting in a 19.8% deviation from the theoretical value and a 12.44% deviation from the simulated value. The research work in this paper enriches the research achievements of non-contact piezoelectric actuators, and also provides a reference for designing small structure and large travel micro-displacement amplifying mechanisms of this type of actuator. [ABSTRACT FROM AUTHOR]

Water utilities are concerned about the issue of pipeline collapses, as service interruptions lead to water shortages. Pipeline collapses can occur during the maintenance phase when water columns compress entrapped air pockets, consequently increasing the pressure head. Analysing entrapped air pockets is complex due to the necessity of numerically solving a system of differential equations. Currently, water utilities need more tools to perform this analysis effectively. This research provides a numerical solution to the problem of entrapped air pockets in pipelines which can be utilised to predict filling operations. The study develops an analytical solution to examine the filling process. A practical application is shown, considering a 600 m long pipeline with an internal diameter of 400 mm. Compared with existing mathematical models, the results of the new analytical equations demonstrate their effectiveness as a new tool for computing the main hydraulic and thermodynamic variables involved in this issue. [ABSTRACT FROM AUTHOR]

Accounts can be understood as "repair of problematic situations", which, in turn, may be seen as inference to the best explanation of a surprising observation. We analyse "learning events" as told by prominent Swedish industrial leaders in two sets of interviews with 30 years between them. We find that the accounts quite often centre around surprising situations, i.e. uncertainty is maximal, where coherence is reached by combining facts and arguments into an understanding of the situation good enough to justify action. The primary function of these accounts is to generate meaning. That meaning will inform managers in the choice of relevant "levers of control" in implementation. It has been argued that "semi-confusing information" in organizations will invite questions and dialogue, and thereby help them avoid or overcome crises. We extend this line of reasoning by showing how such information feeds deliberation – construction of inference to the best explanation – by abductive reasoning toward action in "moments-of-truth". [ABSTRACT FROM AUTHOR]

The wind pressure caused by the high-speed passage of intercity railway trains applies a significant load on the platform screen doors, to ensure the safe of the platform screen doors and achieve reasonable design and construction goals, it is necessary to explore the distribution law and mechanism of wind pressure load on the platform screen doors first. Using Fluent software, RNG k-ε turbulence model was selected, and the control equations were discretized by finite volume method, the second-order upwind scheme and center difference scheme were used to solve the convective and diffusive fluxes, the influence of wind pressure load on platform screen doors caused by intercity train passing through stations was studied. The research results indicates: When a train passes through a station at high speed, the increase in the ross-section area of the enclosed area allows the compressed air to dissipate faster, thereby reducing the wind pressure load on the platform screen doors and minimizing the extreme values of the wind pressure load on the doors; Before the train arrives at the platform screen door, the slight change in the retreat distance between the platform screen door and the platform edge has little effect on the extreme wind pressure load of the platform screen door; After the train arrives at the platform screen door, the airflow changes and distribution in the enclosed area become more severe and complex, the increase in cross-section area makes the wind pressure load of the platform screen door more significantly affected by the change in the retreat distance of the platform screen door; The increase in train passing speed will lead to an increase in the extreme wind pressure load on the platform screen doors; During the process of the train passing through the station, the maximum load at each point of the platform screen door decreases overall along the direction of the train's travel, however, as the speed of the train passing through the station increases, the minimum load (suction) near the end of the platform screen door in the direction of the train's travel tends to increase, and this phenomenon becomes more pronounced as the speed increases. [ABSTRACT FROM AUTHOR]

Renewable energy is a prominent area of research within the energy sector, and the storage of renewable energy represents an efficient method for its utilization. There are various energy storage methods available, among which compressed air energy storage stands out due to its large capacity and cost-effective working medium. While land-based compressed air energy storage power stations have been constructed worldwide, their efficiency remains low. Underwater compressed air energy storage has the potential to significantly enhance efficiency, although no such device currently exists. This paper presents the design of an UWCA-FABESD utilizing five flexible air bags for underwater gas storage and discharge. Additionally, it introduces the working principle of the adiabatic underwater compressed air energy storage system and device. Furthermore, a small-scale physical model with similar functionality was designed and manufactured to simulate the charging process of the air bag in onshore charging and discharging tests as well as posture adjustment and lifting arrangement tests, along with underwater charging and discharging tests. These experiments validated the related functions of the designed underwater compressed air flexible bag energy storage device while proposing methods for its improvement. This research provides a new approach to underwater compressed air energy storage. [ABSTRACT FROM AUTHOR]

In this work, a new solar cooling system that is powered by a concentrated photovoltaic thermal module is presented. Given the intermittent nature of solar energy, the essence of this system lies in its capability to offer continuous cooling. Furthermore, the proposed cooling system is versatile in operation, with three alternative modes available depending on the user's demands. Two operating scenarios of the system are presented. In the first scenario, thermal energy is utilized for cooling during the daytime, while electric energy is stored as compressed air for nighttime use. In the second scenario, both thermal and electric energies are employed for cooling during periods of high demand. The system is studied under different evaporator temperatures, various ambient temperatures, and different solar intensities. The results show that at an evaporation temperature of 4 °C, the system can provide continuous cooling, generating up to 10.24 kW of cooling power during the daytime and up to 7.66 kW during the nighttime, with an overall coefficient of performance of 0.612. [ABSTRACT FROM AUTHOR]

This work investigates the performance of modified tungsten carbide inserts when turning supermartensitic stainless steel with cutting fluid and/or air jet applied in two directions: either cutting fluid under high pressure or compressed air under low pressure supplied on the back of the chip (through a hole produced near the principal cutting edge), together with either cutting fluid or compressed air, both under low pressure, directed at the clearance face. Tool performance is evaluated by means of the principal cutting force, temperature distribution (using FEM), visual evaluation of the rake face, morphology of the chips and the quality of the machined surface. The findings indicate that the groove reduces the cutting force when dry cutting. Cutting fluid applied under low pressure at the clearance face is more efficient in decreasing both the cutting force and chip temperature than cutting fluid at high pressure supplied at the back of the chip. A chrome oxide layer is formed on the chip when air jet is applied, thus leading to an unfavorable cutting condition. The simultaneous application of cutting fluid under high pressure to reach the back of the chip and compressed air supplied through the clearance face provides the best surface quality. [ABSTRACT FROM AUTHOR]

The purpose of the article was to present the results of braking equipment testing and determination of the adequacy of compressed air production of the braking system when the train is loaded. Experimental tests of the braking system of TE33A diesel locomotive in a goods train are performed. According to the initial data the main parameters of the braking system in the empty and loaded train were evaluated. As a result of tests, and according to the calculated data, the dependences of the volume of the main reservoirs, and the dependences of the required compressor capacity, on the number of axles have been obtained. It has been established that the braking system operation in release modes for a 400-axle train corresponds to the operating conditions and the main requirements of the normative documents. [ABSTRACT FROM AUTHOR]

In modern industrial plants, compressed air is the most commonly used energy source; however, it is a source of condensation, which is not desirable for pneumatic equipment. This article describes a model of compressed air drying based on the principle of a refrigeration dryer. However, instead of gas refrigerants, the method proposed is to use cooled compressed air as a cooling medium with a temperature below 273 K. The main objective is to study the possibility of replacing harmful refrigerant gases with a neutral type of coolant. To carry out this research, a test bench containing a plate heat exchanger and a throttling device was designed and manufactured. This study has yielded the following scientific results. Firstly, the Joule–Thompson effect was used during the experiments, which facilitated a reduction in the temperature of the compressed air to 255 K. Secondly, using the expanded air and a plate heat exchanger, the temperature of the main compressed air stream was reduced to 280 K, which is very close to the temperature provided by standard-refrigeration-type compressed air dryers. This suggests that it is possible to use compressed air energy to cool the main stream of warm compressed air after the compressor. In general, the temperature range ensures the compressed air quality at the level of class 4 in accordance with international standards. [ABSTRACT FROM AUTHOR]

To evaluate potential airborne asbestos exposures during brake maintenance and repair activities on a P&H overhead crane, and during subsequent handling of the mechanic's clothing. Personal (n = 27) and area (n = 61) airborne fiber concentrations were measured during brake tests, removal, hand sanding, compressed air use, removal and reattachment of chrysotile-containing brake linings, and reinstallation of the brake linings. The mechanic's clothing was used to measure potential exposure during clothes handling. All brake linings contained between 19.9% to 52.4% chrysotile asbestos. No amphibole fibers were detected in any bulk or airborne samples. The average full-shift airborne chrysotile concentration was 0.035 f/cc (PCM-equivalent asbestos-specific fibers, or PCME). Average task-based personal air samples collected during brake maintenance, sanding, compressed air use, and brake lining removal tasks ranged from 0 to 0.48 f/cc (PCME). The calculated 30-minute time-weighted average (TWA) airborne chrysotile concentration associated with 5-15 minutes of clothes handling was 0–0.035 f/cc PCME. The results indicated that personal and area TWA fiber concentrations measured during all crane brake maintenance and clothes handling tasks were below the current OSHA 8-h TWA Permissible Exposure Limit for asbestos of 0.1 f/cc. Further, no airborne asbestos fibers were measured during routine brake maintenance tasks following the manufacturer's maintenance manual procedures. All short-term airborne chrysotile concentrations measured during non-routine tasks were below the current 30-minute OSHA excursion limit for asbestos of 1 f/cc. This study adds to the available data regarding chrysotile exposure potential during maintenance on overhead cranes. [ABSTRACT FROM AUTHOR]

To reduce greenhouse gas emissions and the environmental impact of fossil fuels, Morocco has decided to increase the use of renewable energy resources. The intermittent nature of renewable energy resources causes instability in the power grid. Energy storage is the appropriate solution to this problem. Compressed air energy storage is a technology that stores energy in the form of high-pressure compressed air in above ground tanks or underground caverns. Large-scale storage of compressed air energy requires the storage of large volumes in salt caverns or aquifers. The aim of this paper is to find out the benefits of integrating underground compressed air energy storage technology. A case study in Morocco is used to estimate the levelized cost of energy plus storage (LCOES). The annual capacity factor for solar and wind power plants and the potential of underground caverns in Morocco were analyzed. The results illustrate that for a system with 100 MW capacity installed in the Casablanca region, the combination of an adiabatic compressed air energy storage system (ACAES) with a wind turbine installation offers the lowest electricity price per kWh, with average LCOES of 0.04 $/kWh. [ABSTRACT FROM AUTHOR]

The imperative shift toward sustainability has driven contemporary scholars to explore the lubricating and cooling properties of vegetable oils in traditional metal-cutting processes. Palm oil, as an environmentally conscious derivative, emerges as a preferable option for the base fluid in Minimum Quantity Lubrication (MQL). However, its high viscosity impedes fluidity, limiting industrial applicability. In contrast, sunflower oil offers superior lubricating qualities and flowability. Consequently, efforts have been directed toward enhancing the lubricating efficacy of palm oil. Six blends of palm and sunflower oils (ranging from 1:0.5 to 1:3) were utilized as MQL fluids, followed by evaluations of machining outcomes, including average surface roughness, specific cutting energy, and tool wear. In addition, an integrated Shannon's Entropy-based Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) framework was employed to determine the optimal volume ratio of the palm–sunflower oil blend. The TOPSIS analysis confirmed that the 1:2 ratio yielded the most favorable outcomes. Subsequent comparative analysis demonstrated that this optimal blend resulted in reductions of 16.79% and 14.92% in surface roughness, 11.82% and 10.98% in specific cutting energy, and 10.19% and 8.45% in tool wear compared to pure palm and sunflower oil media, respectively. Finally, sustainability assessments of various cooling media revealed that a minimal quantity of the blended bio-lubricant-based medium outperforms both compressed air and flooded media. [ABSTRACT FROM AUTHOR]

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The copper mold of the micro-triangular pyramid (MTP) is a key component of MTP plastic film manufacturing, and its optical functional surface comprises micro-triangular pyramid arrays (MTPAs). The edge burrs of MTPAs severely affect the optical properties of MTP plastic film. To solve the problem of excessive edge burr of MTPA machining using the fly-cutting method, the orthogonal experimental method was used to optimize the four influencing factors: fly-cutting speed, feed speed, cutting depth, and cooling mode. The results show that the impact of these influencing factors on surface roughness, the projected area of the exit edge burr, and exit edge burr thickness are ranked from largest to the smallest as follows: fly-cutting speed, feed speed, cutting depth, and cooling mode. The factors affecting tool nose wear in descending order are fly-cutting speed, feed speed, cooling mode, and cutting depth. The optimal conditions for minimizing the thickness of the edge burr were a fly-cutting speed of 7.85 m/s, a feed speed of 50 mm/min, a finishing cutting depth of 15 μm, and using compressed air with oil mist for cooling. This study lays a foundation for improving the anti-reflection performance of MTP plastic film. [ABSTRACT FROM AUTHOR]

Traditional electric robots often rely on heavy gear units or expensive force–torque sensors, whereas pneumatic robots offer a cost-effective and simple alternative. However, their dependence on noisy and bulky pneumatic systems, such as compressed air technology, limits their portability and adaptability. To overcome these challenges, we have developed a reversible electrochemical pneumatic battery (REPB) that is compact, noise-free, energy-efficient, and portable. This innovative REPB, principled by the electrochemical redox reactions of zinc–air batteries, can simultaneously supply both electric and pneumatic power, either positive or negative pressure. Its modular, multi-stack structure allows for the easy customization of power output and capacity to suit various applications. We demonstrate the utility of REPB through its application in jamming robots, such as a novel soft yet robust gripper that merges the strengths of hard and soft grippers, enabling universal robotic gripping. This work presents a groundbreaking approach to powering devices that require pneumatic support. [ABSTRACT FROM AUTHOR]

This paper explores a novel method of focuses on utilizing ammonia as a hydrogen carrier that can be decomposed to produce hydrogen, the combustion of which produces steam for generating power in turbines. The simulation for such a process is performed on ASPEN Plus software. The key steps include compressing the ammonia and passing it through a fluidized bed reactor (FBR) for its decomposition, subsequently compressing the products before combusting the hydrogen with compressed air in a combustor and extracting power from the hot products through a series of turbines. The article examines in detail the effect of different parameters on the performance of the individual components as well as the overall process. Specifically, considerable emphasis is placed on the effects of varying pressures and temperatures on the functioning of the FBR at different catalyst loadings, their effects on the combustor performance and the dependence of the overall process on the air flowrate in the combustor. The comprehensive analysis elucidated on the energy efficiency of the process and it identified conditions at 2 bar pressure and 550 °C temperature as being the most favorable for ammonia decomposition and subsequent turbine power output while lean hydrogen combustion with excess air making the inlet hydrogen concentration less than 20% resulted in optimum temperatures at the turbine inlet. • The paper explores ammonia as a hydrogen carrier in the power plant industry through ASPEN PLUS process simulations. • The initial step is to decompose ammonia into nitrogen and hydrogen in a fluidized bed reactor, the optimum operating condition of which turns out to be 2 bar pressure and 550 °C. • The next steps involve mixing air with the decomposition products, pressurizing them to 40-60 bar, combusting hydrogen in a plug flow reactor to produce steam and finally expanding it in a series of turbines to generate power. • Detailed flow and more importantly, energy analysis of all the process units show ammonia as a very effective hydrogen carrier for applications in power plants. [ABSTRACT FROM AUTHOR]

The object of this study is the properties of compressed air foam with the use of modified additives: its drainage time and expansion ratio. The main properties of compressed air foam that affect the effectiveness of fire extinguishing are its drainage time and expansion ratio. At the same time, a number of authors have confirmed that the introduction of chemically modified additives into the composition of water fire extinguishing substances makes it possible to increase the effectiveness of fire extinguishing. The problem to be solved was to determine the influence of five modified additives (N4)2HPO4, N4H2PO4, (N4)2СO3, K2CO3 and KCl in the concentration range of 1–5 % by mass on the expansion ratio and drainage time of the compressed air foam. The results showed that the content of additives (N4)2HPO4, N4H2PO4 and (N4)2СO3 in the aqueous solution of the foaming agent does not affect its expansion ratio within the given limits. On the other hand, with K2CO3 and KCl additives, it was not possible to obtain compressed air foam with a expansion ratio of 5–20, that is, their inefficiency in compressed air foam was noted. The characteristic dependence of the effect of (N4)2HPO4, NH4H2PO4 and (N4)2СO3 additives on drainage time has been determined. The greatest drainage time is characteristic of the K≈20 generation mode. The highest recorded drainage time index was established for N4H2PO4, namely 5.45 min; for (NH4)2HPO4 the drainage time was lower by 8 %; for (N4)2СO3 the drainage time was lower by 20 %. At the same time, with the use of (N4)2HPO4, N4H2PO4 and (NH4)2СO3, it is characteristic to obtain a foam with lower drainage time compared to foam of a conventional composition. Thus, for foam with a expansion ratio of K≈20, the drainage time of foam with NH4H2PO4 is lower by 17 %, with (NH4)2HPO4 by 23 %, and with (NH4)2СO3 by 33 %. The effect of reducing the drainage time of the foam can have a decisive role in reducing its effectiveness when used for extinguishing flammable liquids due to the extinguishing mechanism but is not decisive for extinguishing solid substances. Therefore, the fire-extinguishing effectiveness of compressed air foam with modified additives during the extinguishing of solid combustible materials in comparison with the conventional CAF composition requires further study [ABSTRACT FROM AUTHOR]

The methods of increasing energy and operation parameters of a pneumatic hammer with an air distribution valve are reviewed. The algorithm of restructuring impact capacity of a pneumatic hammer with an elastic ring valve in the back stroke chamber of the hammer piston is proposed: it is suggested to use a feed source with an increased-pressure energy carrier. The algorithm was employed in designing and manufacturing a prototype model of the hammer. The actual operation factors of the prototype model are determined on a lab-scale bench tester: impact energy, impact frequency, energy source flow rate. After processing of indicator pressure charts, compressed air flow rate per unit energy output is assessed. [ABSTRACT FROM AUTHOR]

Objectives: In the protocol for cleaning and sterilizing dental handpieces (DHs), water retention within the instrument poses a challenge and may compromise the sterilization process. This study aimed to assess the reliability and reproducibility of the sterilization protocol regarding the dryness of DHs. It evaluated the presence of residual water in these instruments after various conditions of treatment through multiple dryness tests. Methods: This comparative study examined the dryness of seven different DHs following five washing–disinfection and/or sterilization protocols. Dabbing tests, shaking by hand, or compressed air tests through DHs and over absorbent paper were employed to ascertain the thorough dryness of DHs after treatment. As soon as the first sign of water appeared on the absorbent paper, the DH was deemed to be not dry. Results: Upon completion of the washing–disinfection protocol without sterilization, five out of seven DHs were deemed dry using the dabbing test, yet none were fully dry when subjected to shaking or compressed air. However, in the four protocols incorporating final sterilization, all DHs were dry according to the three drying tests. Conclusion: This study underscores the essential role of the sterilization step in eliminating residual water from DHs, thereby ensuring optimal conditions for effective sterilization in terms of dryness. Furthermore, the study recommends against relying solely on the dabbing drying test, emphasizing the importance of shaking or using compressed air to confirm instrument dryness. [ABSTRACT FROM AUTHOR]

The present study investigated the influence of SCUBA dives with compressed air at depths of 10 and 20 m on ECG-derived HRV parameters in apparently healthy individuals. We hypothesized that cardiac sympathetic activity (measured by HRV parameters) adapts proportionally to diving depth, and that both time- and frequency-domain parameters are sensitive enough to track changes in cardiac ANS function during diving activities and subsequently during the recovery period. Eleven healthy middle-aged recreational divers (nine men and two women, age 43 ± 8, all nonsmokers) volunteered to participate in the present study. The participants (all open-circuit divers) were equipped with dry suits and ECG Holter devices and were later randomly assigned to dive pairs and depths (10 m vs. 20 m), and each participant served as his or her own control. No interaction effects (diving depth x time epoch) were found for the most commonly used HRV markers. More precisely, in response to two different diving protocols, a significant post hoc effect of time was observed for HR and SDNN, as these parameters transiently decreased during the dives and returned to baseline after ascent (p < 0.001). The ULF, VLF (p < 0.003), TP, and LF parameters decreased significantly during the dives, while HF significantly increased (p < 0.003). SCUBA diving apparently challenges the cardiac ANS, even in healthy individuals. The observed changes reveal possible underwater methods of influencing the parasympathetic activity of the heart depending on the depth of the dive. These results identify autonomic nervous system markers to track the cardiovascular risk related to diving and point to the possibility of tracking cardiovascular system benefits during underwater activities in selected patients. [ABSTRACT FROM AUTHOR]

To accurately assess the dynamic stability of the damaged ship, this paper performs an experimental campaign and presents a feasible numerical method to analyze the effects of microscopic air–fluid interactions on the motion responses of the damaged ship. The numerical approach can be applied to solve the coupled hydrodynamic behavior between the flooding process and the motion responses of the damaged ship. The volume of fluid (VOF) method was applied to capture the interface of the free surface, while the dynamic fluid–body Interaction (DFBI) morphing technique was applied to deal with mesh adaption. In particular, the UDF (user-defined field) function was activated to realize the initial distribution of the free surface. Firstly, by comparing the experimental and numerical results, the reliability of visualizing the flooding process and dealing with the motion responses of the damaged ship was efficiently verified. The numerical flooding process was able to reproduce the hydrodynamic phenomenon well, including the flooding jet, interaction, and flow between adjacent compartments. The numerical roll motion curve of the damaged ship was consistent with that predicted in the model test, with an error in roll amplitude of no more than 4%. Secondly, based on the verified numerical method, it was seen from the results with different ventilation positions that not only the air compressibility due to varying levels of ventilation cannot be neglected in damage assessment, but also the position of the ventilation hole was crucial. This was because different positions will create different paths for the compressed air to overflow and affect air–fluid interactions. Thus, the flooding force and air-impacting force acting on the internal hull will be different. In conclusion, this paper introduces a new consideration in the damage assessment of ships. [ABSTRACT FROM AUTHOR]

The main objective of this research is to determine the overall performance value of the pneumatic actuator system on a solar-powered pineapple cutting machine. The research methods used are literature study and experimental laboratory. The laboratory experimental method is very suitable to be applied to post-harvest agricultural machines with a small capacity where the research is only focused on the success of the actuator system in carrying out pineapple cutting movements automatically by utilizing pressurized air coming from the compressor. The variation in air pressure for the pneumatic actuator is set at the air pressure, namely 3, 4, and 5 Bar. The actual peeling capacity using air pressure of 3 Bar resulted in 160 pineapple cutting/per hour, 170 fruit/per hour for 4 Bar, 173 bar for 5 bar, and 173 fruit/per hour manually. The efficiency of peeling pineapple manually was 82.8% while using a pneumatic actuator system it was 70.6%. The DC electrical energy storage capacity required for the pneumatic actuator drive system is a battery with a capacity of 80 Ah 12 v which is supplied by electrical energy originating from a 200 Wp solar panel. Solar panels of this size are sufficient to equip a pneumatic actuator system for stripping with capacity of 1 hour/day. The results of this study are expected provide the latest reference for determining the optimal productivity of solar-powered pineapple cutting machines today.

Recreational abuse of compressed air duster has been associated with cardiac toxicity, central nervous system depression, local tissue damage, seizures, and death. We describe a 30-year-old man who reported huffing four bottles of canned air duster to “get high.” In addition to blistering on his dominant hand, he developed pain and swelling of the lips and tongue, followed by difficulty speaking and swallowing. He underwent endotracheal intubation for anticipated airway failure and was treated for an allergic reaction. Fiberoptic bronchoscopy and computed tomography scan of the neck demonstrated unaffected posterior oropharynx and airways. He was extubated on hospital day 2 and subsequently made a full recovery. Patients with oropharyngeal and dermal injury after abuse of compressed air duster are likely suffering a thermally-mediated injury. Outcomes are generally good with minimal intervention. Routine treatment for an allergic reaction is unnecessary.